1. Field of the Invention
The invention relates in general to a scan method for a flat panel display drive device, and more particularly to a scan method that determines a scanning sequence according to a gray level difference of image data to reduce power dissipation.
2. Description of the Related Art
Referring to FIG. 2, a driving circuit for a conventional flat panel display is shown. A column driving unit 62 and a row driving unit 64 work together to control a flat panel 50 in general. The column driving unit 62 and the row driving unit 64 connects to a plurality of data lines 63 and scan lines 65, respectively. Multiple pixels 51 are formed on the flat panel 50. Each pixel 51 is mapping to a cross-position formed by the data lines 63 and the scan lines 65.
When controlling the flat panel 50 to output an image, the row driving unit 64 sequentially outputs scan signals to the scan lines 65. Each pixel 51 on the same row is determined to be charged or discharged according to a grayscale signal outputted by its own data line 63. A scan update speed is very prompt; hence static image quality of the output image can be displayed on the flat panel 50 due to ‘retention of image’ phenomenon experienced in human vision.
Consumer demand for increasingly higher resolution flat panel displays has resulted in the quantity of pixels on flat panels accordingly rising. Hence less time is distributed to conduct each scan line 65 while an update frequency on the image is unchanging. Therefore it is difficult for each pixel 51 to be fully charged/discharged within a very short time, thereby impairing the image quality and greatly decreasing a contrast degree on the image.
Moreover, a power dissipation problem is also a critical issue of the flat panel 50. The conventional row driving unit 64 as foresaid outputs the scan signals to the scan line 65 from the top to the bottom in sequence. Hence the power dissipation problem is manifest due to extremely charged/discharged operations when a huge grayscale variation exists between the pixels 51 of the two adjacent scan lines 65.
The flat panel is applied in various compact and portable electronic devices such as cell phones, PDAs, digital MP3 players, and so on. If the power dissipation of the flat panel can be effectively reduced, the entire power consumption of the electronic device can be accordingly improved.